German Published Patent Application No. 28 29 057 describes a fuel-injection system which supplies fuel to a mixture-compressing internal combustion engine having external ignition as a function of operating parameters. The fuel-injection system encompasses a metal fuel-distributor line, which, via at least one branch line, is connected to at least one fuel injector, the branch line being embodied as a metal tube and connected to the fuel injector by manner of a threaded connection. Easily bendable metal is used as material for the branch line. Arranged between the threaded connection on the branch line and the fuel injector are thin-walled metal bellows in the form of a corrugated-tube bellows by which a lateral offset between the beginning of the branch line on the fuel-distributor line and the fitting position of the fuel injector is compensated; in addition, the operating noises emanating from the fuel injector are damped by the yielding of the bellows.
German Published Patent Application No. 28 29 057 describes a fuel-injection system such that while the flexurally soft bellows having thin material thickness does reduce a transmission of solid-borne noise to the fuel-distributor line, it is excited to oscillations itself and radiates noise. The natural resonance characteristic of the corrugated-tube bellows may be influenced only to a negligible degree. The corrugated-tube bellows, if it is made of an elastic sheet metal, has only low self-damping.
Finally, due to the vibrations of the internal combustion engine during operation, the corrugated-tube bellows are in danger of breaking or ripping if insufficient self-damping occurs. In the case of directly injecting fuel injectors and at the high pressures required in this context, the connection between a fuel injector and the fuel-distributor line is safety-relevant and must not break under any circumstances.
U.S. Pat. No. 2,014,355 describes a pipe connection in the form of a corrugated tube by which the transmission of vibrations is meant to be prevented or reduced. On the outside, the corrugated tube is surrounded by an envelope that does not touch the corrugated tube and is rigidly connected to one pipe section at one end. At its other end, the envelope is sealed from the other pipe section by a flexible seal, the envelope shielding from noise originating in the corrugated tube.
Other systems provide that the natural oscillation characteristic of the corrugated tube may not be influenced. The oscillation characteristic is merely influenced indirectly with respect to one another, via the stiffness of the two pipe sections, since these tube sections are damped in their relative movements via the sleeve and the seal. Moreover, the configuration consists of several parts and is complicated.